In the conventional art, the connecting device of the temperature sensor for sensing the temperature of the food in cooking has on one end a temperature sensor 35 being inserted into the food 34 placed on a turntable 33 in the cooking cavity of a microwave oven 31 shown in FIG. 3 and on the other end of the cord 36 a temperature probe 37 and a plug 37' being received through an opening 39 of the ceiling 38 of the cooking cavity 32 into the plug holder 40 for contact with it. The conventional device is constructed as in the above that the rotation of the turntable 33 driven by the motor 41 also turns the food 34 with the inserted temperature sensor 35 to cause the lead cord 36 with its plug 37' of the temperature probe 37 rotate in the plug holder 40 so as not to twist the lead cord 36.
However, with a stirrer fan mounted on the top of the cooking cavity the arrangement in the conventional construction comes to be infeasible for practical application. In the event of mounting a stirrer fan on the ceiling of the cooking cavity, a plug holder 40 has to be provided on a side wall, thus, to make difficult the rotation of the temperature probe 37.